Arc tight cable connector



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ATTORNEYS.

Patented Nov. 4, 1952 UNITED STATES PATENT GFFICE 2,616,942 Y it'c iri CABLE ooNNo'ioit Jam-es H. simpson, si. Louis, and Ernest B.

Gloningcr, -Afftoni Mo., assignors, by mesnc iassignhmenta to yJoy Manufacturing Company, Pittsburgh, Pa., ya corporation f Pennsylvania applicaties March '2, 194s, serai Ne. lasse (Cl. .lis-lle) 2 claims.

This invention pertains to electrical connectors or the piugesocket type such :as may be used 'as cable, connectors .for electrically and .mi'eclra'ni'i cally connecting diierent lengths of cable to 'each other or by which such 'a length l'of "cable may be connected to a. stationary connector such .as may be provided at the source of power `supply or on a machine. Y

One of the objects of this :invention is to vpro'- vide a connector vof this type which may be used safely in locations where an explosion hazard exists as, for instance, where the atmosph'ere contains a mixture of air and an iniiammable gas. Such hazards are .frequent in mines and similar locations.

Another object is to provide such a connector in which the 'contacts are housed in an Venclosure adapted to separate them zfrom the ambient vatmosphere at the time when -any :live circuit in the Vconnector is made or broken.`

Further objects will appear from the following description, in which an illustrative embodi-- ment of the invention will be set forth. It is understood, however, that the invention is susceptible of various embodiments Within the Ascope of the appended claims, without departing ifrom the principles or the spirit of the invention.

In the accompanying ydrawings Figure v1 is `a view, partly Ain section, of a Acomplementary pair of rconnectors embodying this invention. :Fig-ure 2is anend view of the fright 4hand lor plug connector shown in Figure 1-, and Figure 3 1is a view illustrating the manner in which a stationary connector may be mounted Since in most connectors of this type one member of a pair will be provided with lplugs, and the other with sockets and since the construction and functioning Yof both'of these is the same except for this difference in the contacts, the term connector will be used hereinafter to designate a connector of either 'type or one which, asin some cases, contains both plugs and (sockets.

Referring now to the accompanying drawings, I designates the body of the connectdr. This 'may be of any suitable 'insulating material. Rubber provides a very effective material for this purpose, the contacts being moldedin the rubber `body inv amann'erwell known in the art.

In the embodiment illustrated .the connector and the cable 2 tov/ nich it is-connectedpcarry D not only the wires ci a power circuit but also those of a control "circuit for operating relays l illar devices for controlling the power -circuit. InFigure s1, thewiresoithe'power circuit. are indicated at 3 and 4`. Only one of ft e wires f y"the 'control Hcircuit is Ysht'vii lv vin I*liigure "fl indicated at 5.

In the complementary connector, the body is indicated at ID connected to a. cable 2U. The power wires are indicated at 30 and 40 and the control .circuit wire at Y5i). The `end 'oi' `each of these 'conductors' is equipped with a contact, all of which 'contacts for the power circuit ybe ing .referred to by the numeral 6. These may be plugs or sockets, as the case may be. A con"- ta'ct for the control circuit is `indicated at 7^.

In the embodiment illustrated, 'the contacts 1 for the control circuit are so positioned with relation to the A'contacts A6 for the power circuit that the control circuit contacts of the comple*- mentary connectors do not engage each other until after the power circuit contacts have made contact with each other so as to close the power circuit. Accordingly, the control device which may `be `connected to thecontacts 1 cannot oper ate -to 'close the power circuit until that circuit has been closed at the "contacts 6. Similarly said control 'devices 'will operate to open the pow/- er circuit before the contacts 6 are disengaged when separating the tWo connectors. This insures that the only 'make and break of a live circuit possible in connecting or disconnecting the complementary connectors takes place at the contacts 'I-. In order to insure that lany spark generated in the opening or closing of Athe rcon-- trol circuit at the contacts 'I may not set up a re hazard, an enclosure is provided -for these contacts during the making or breaking operation. Such Aenclosure in the embodiment illus trated is provided by a .pair of screw collars 8 and 9, one on each of the complementary `connectors. These collars are arranged to be rotatable on the bodies I and I respectively. Each may be secured in place by a ball-bearing comprising a row of balls Il `arranged to run in --a groove in a vmetal collar I2 providing-a ball race for the bearing. A similar groove I3 in the outer'collarprovides the outer race for the bearing. The outer groove I3 may be made wider than the balls so as to permit a certain amount of endwise movement of the collar 8 or 9 relative to the body. The collars I2 may be molded in the body of the vconnector or, as is sometimes preferable, a groove to `receive the collar is molded in the body and the collar being split into 4two halvesis assembled in the groove. The outer collar 8 or 9 is then slipped over the collar `I2 to `hold thelatterin place. rIhe balls VII may then be 'inserted by a suitable opening lin the outer -4collarclosed by a plug I4 Vin any `suit-- able manner. Y Y

Where the connector is to be mounted on a stationary mounting, the body maybe formed -as indicated in dcttedrlinesin Figure 3 and the outer collar I2-forined with'a-:suitable iiange I5 adapted fcrlmountin'g `in any "usualmanner upon laffsuitable support.

In the operation of this connector when a circuit is to be extended by a section of cable 2 or 20, the contacts 6 of the two connectors are first engaged with each other to close the power circuit. It is convenient` in most cases to provide one of the connectors with all plugs, except one. and the other with all sockets except one. In the arrangement shown in Figure 2 a four wire power circuit is indicated having three plugs and one socket. A two-wire control circuit having two plugs 'I is also indicated. Having one of the contacts of the type complementary to the others, serves to Yidentify the separate conductors in the connector and the attached cable so as to insure that the desired polarities are maintained throughout the circuit, or, as in three-phase circuits, the same direction of rotation of connected motors may be maintained. In the four wire arrangement of Figure 2 the socket may identify a ground wire. Thus, there is only one way in which the contacts may be put together and, accordingly, it is impossible to interchange the wires of the circuit. The arrangement ofthe wide groove I3 permits the collars 8 and 9 to be retracted relatively to the contacts so that the latter may be guided visually to their proper relation when the initial engagement of the power contacts is made. When the power contacts of the two complementary connectors have been engaged, the collars may be slipped toward each other and are then in position for engagement of their threads. The wide groove I3 now also provides extra travel for the collars relative to the contacts so that a considerable number of threads maybe engaged before the contacts 'I are ready to make the control circuit. This, therefore, provides a space I6 within the enclosure provided by the two collars 8 and 9 which is entirely sepa- Once the control contacts have been engaged and the threads of the collars started in engagement with each other, said collars may be screwed up toward each other, thereby drawing the lbodies I and II) together and forcing the contacts 6 into full engagement with each other. The bodies I and I may be provided with upstanding collars I1 of the body material, such as rubber, arranged to enter complementary recesses I8 at the mating socket so as to provide a moisture seal. Similarly the bodies may be provided with circumferential beads I9, which engage each other under pressure when the collars 8 and 9 are fully screwed up, thereby providing an additional water seal.

It will be seen, therefore, that the invention accomplishes its objects in providing a connector which may handle a power circuit capable of carrying aheavy load and which will insure that in engaging or disengaging complementary connectors there is no possibility of making or breaking the power circuit under load since the control contacts insure the operation of the control devices in such manner that the power circuit is dead while its contacts are being engaged or disengaged. The invention may be applied to connectors for circuits carrying a light load in which a separate control circuit is unnecessary. In such a case, the control circuit wires 5 and 5I) and their contacts 'I will be omitted. In such a case, however, the grooves I3 may be arranged to permit engagement of the threads of the collars 8 or 9 before the power contacts 6 come together so as to provide the sealed enclosure I6 at the time such contacts are engaged or disengaged. In such a case a dummy pilot plug and socket may be provided to insure proper polarity.

Having thus described the invention, what is claimed is:

l. A connector of the character described, comprising an insulating body, one or more contacts carried bysaid body, a screw collar on said body mounted for rotation on said body, provided on its inner surface with a wide radial race and constructed and arranged for cooperation with an externally threaded complementary connector to draw the mating contacts of the two connectors together, and positioned to provide an inclosure exteriorly of the opposing faces of said connectors to separate said contacts in circuit making and breaking position from the ambient atmosphere, and a race on said body complemental to but narrower than the race on said collar to provide, when assembled. an anti-friction bearing which permits retraction of said collar, to facilitate initial engagementof said contacts.

2. A connector of the character described comprising an insulating body provided with a circumferential groove forming a radial ball-bearing race; one or more contacts carried -by said body; a screw collar on said body mounted rotatably on said body, Said screw collar being provided on its inner surface with a groove forming a radial ball-bearing race complementary to the race on said body, and being constructed and arranged for cooperation with a threaded complementary connector to draw the mating contacts of the two connectors together, and positioned to provide with said complementary conector an inclosure exteriorly of the opposing faces of said connectors to separate said contacts in circuit making and breaking position from the ambient atmosphere; at least one of said complementary races being sufficiently much wider than the diameter of ball bearings in said races to provide, when assembled, an anti-friction bearing which permits retraction of said collar, to facilitate initial engagement of said contacts.

VJAMES H. SIMPSON. ERNEST B. CLONINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,002,177 Hastings May 21, 1935 2,068,399 vDash et al Jan. 19, 1937 2,149,492 Annen Mar, '7, 1939 2,337,618 Miller Dec. 28, 1943 FOREIGN PATENTS Number Country Date 22,138 England a Oct. '7, 1912 of 1911 428,203 f England Y May 8, 1935 

